15 



being here much greater pests than in their native homes. This result 

 is due in part, at least, to the fact that their native parasitic and pre- 

 daceous enemies have not been introduced along with them, and they 

 are thus able to develop largely unmolested by these important checks. 

 The proposition, therefore, has been to determine the original home 

 of an injurious introduced species, and then to obtain its enemies and 

 to array them against it in hope of thereby securing its control. 



Regarding the insect under discussion^the cotton hoUworm — there 

 are but few data with a possible bearing on its native home, and these 

 are largely of a contradictor}^ nature. That it is really indigenous 

 over its present extended range is scarcely to be admitted. While 

 there are numerous truly cosmopolitan families and a large, though 

 proportionately less, number of genera, the truly cosmopolitan species 

 of animals are comparatively few. In the case of many widely dis- 

 tributed insects the possible accidental influence of man in furthering 

 their distribution really makes it doubtful whether they are indigenous 

 throughout their known range. Anosia plexij)2>us Linn, and Ya7iessa 

 {Pyrameis) car did Linn., among butterflies, appear to enjo}^ an almost 

 world-wide distribution, but the ease with which pupae of these could 

 be transported and, further, the vigorous flight of the butterflies 

 themselves when once established would enable them to soon become 

 quite common over an entire continent. 



Reference to Plate I will show how widely the bollworm is at pres- 

 ent known to be distributed over the world. Rejecting the idea of its 

 being truly indigenous over this vast territory, it may be worth while 

 to consider some facts bearing on the subject of its original home. 



As has been noted in the original description of this species by Fabri- 

 cius under the name Bomhyx obsoleta^ its habitat is given as Americse 

 Meridionalis Insulis. Accepting the identity of Bombyx obsoleta with 

 our bollworm moth, as held by Sir G. F. Hampson and others, the 

 species was first described from a specimen or specimens probably f roro, 

 the West Indies. Apparently the earliest reference to the bollworm 

 as depredating on crops comes from the United States. B}^ 1820 its 

 ravages on cotton were the occasion of a short note in the American 

 Farmer by a correspondent writing under date of September 20, 1820, 

 to the efl'ect that the pods of his cotton had been attacked by a large 

 green worm from 1 to li inches long, which ate its way into the pod 

 and did not leave it until it had completed the destruction. Some of 

 the worms Avere smaller; some were brown and red. The injury 

 seemed to be severe, with the prospect of one-fourth of the crop 

 being destroyed. 



By 1811 the bollworm had become prominent as an enemy to cot- 

 ton and corn in the Southern United States, and it is recorded as 

 attacking corn in Illinois in 1812. 

 22051— No. 50—05 2 



